SPACE PHOTOS THIS WEEK: Alien Dust, Zodiac Light, More

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SPACE PHOTOS THIS WEEK: Alien Dust, Zodiac Light, More

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Planet Collision

January 6, 2010—Two large, rocky bodies collide while in orbit around the star HD 131488 in an artist's conception. Such a collision would explain a ring of warm dust recently found inside the star's terrestrial planet zone, the region in which the star would heat matter to temperatures like those on Earth.

Astronomers using the Gemini South telescope in Chile found that the dust in this warm ring is completely alien—it's unlike any dust yet seen around another star. In addition, HD 131488 hosts a ring of cold dust at a similar distance as the Kuiper belt is from our sun. This cooler dust is most likely left over from planets that formed farther from the star, scientists suspect.

The recently released picture, taken minutes after sunset, shows what's known as zodiacal light. This triangular glow appears over the constellations that make up the zodiac, which follow the sun's annual path across the sky, known as the ecliptic. The phenomenon is best viewed in night skies free from light pollution and intense moonlight, such as those over La Silla.

Photograph courtesy Y. Beletsky, ESO

Mars Dunes

January 6, 2010—Thawing carbon dioxide ice on Mars causes sand to tumble down dunes in the northern latitudes, leaving dark streaks, as seen in a recently released false-color picture taken by the Mars Reconnaissance Orbiter.

Ice covers these dunes in Martian winter, and the spring thaw causes the ice to sublimate, or turn directly from a solid into a gas. The activity kicks up dark dust and leaves polygonal cracks in the residual ice.

The December 18, 2009, test flight allowed project managers to see if opening the doors affected the plane's handling, disrupted the telescope, or caused anything inside the craft to shake loose. "Everything went well," SOFIA program manager Bob Meyer said in a statement released last week.

SOFIA's 98-inch telescope is designed to collect infrared light from a variety of astronomical objects while soaring at 40,000 feet (12,192 meters). This unique position will help astronomers study objects that are impossible for even the highest ground-based observatories to see, while limiting the cost of launching and maintaining an orbiting space-based telescope.

Photograph courtesy NASA

Minerals on Mars

January 11, 2010—It might look like a closeup shot of a seashell, but this recently released image is actually a sky-high view of Juventae Chasma in the Valles Marineris region of Mars.

Taken by NASA's Mars Reconnaissance Orbiter, the picture shows bright deposits of silica and sulfates under a darker mantle. These minerals suggest that cold, acidic water was at work on the Martian plateau during the Hesperian era, a period in ancient Mars's history marked by a shift to drier conditions.